There are normal glasses to fix it. I tried once and it seemed plausible, though I wanted contact lenses, and that wasn't an option back then. So there are 3 different photoreceptor cells in your retina, each responsible for one of RGB. Many "colorblind" people actually have just a lower numbers in one of the receptors and the more present receptors distort colors, like if you try to mix a color from RGB paint but don't have enough from one of the ingredients. These glasses correct the distortion. Though they can not change color perception for people whose deficiency is caused by a complete absence of one of the photoreceptors.